1. Field of the Invention
The present invention relates to asphalt patching, paving or repair compositions, sealing or coating compositions, a method for making the compositions, and a method for repairing, paving or patching roadways, such as asphaltic surfaces. The compositions and methods are applicable particularly to repairing or patching potholes, and the like, usually caused by weather and temperature variations and to repairing utility cuts in roadways. More particularly, the present invention relates to asphalt compositions that can be packaged and used for small road repairs or can be stored in bulk stock piles, and used for the desired repairs without on-site heating or other thermal control of the asphalt compositions.
2. Description of the Prior Art
Numerous disadvantages are associated with prior art methods and asphalt compositions generally used for the patching of roads and other surfaces. Hot asphalt compositions that are generally used in patching roads become stable upon cooling. In order to prevent the premature cooling of such compositions prior to use, special equipment is not only required to produce these compositions, but also to transport these compositions, in a heated state, to the site of a repair. It is necessary to maintain the compositions at the desired elevated temperature until the completion of the job, resulting in considerable labor and other expenses for the exercise of thermal control. Further, transportation of these heated mixtures is limited by traffic conditions and weather conditions, such as rain and snow.
Once at the working site, the hot asphalt compositions must be maintained at the proper temperature until used. When used in a patching operation, a crew of, for example, four to seven skilled personnel are required for the raking, hot ironing, tamping and subsequent hot-rolling of the composition so that the composition is softened and satisfactorily secured to the existing roadway being repaired. Another drawback with such hot asphalt compositions is that these compositions cannot be used in patching operations while raining or snowing because the rain or snow tends to abnormally cool the hot compositions and prevents the hot compositions from satisfactorily adhering to the roadway. Further, such hot mixes are generally transported in full truckloads to the site of a repair in order to conserve heat. Quite often, much of the material becomes too cold and therefore too hard to use and is therefore wasted. Additional costs are thereby incurred for the asphalt not used as well as the disposal of the asphalt.
A still further serious drawback in the use of the prior art patching compositions relates to the expansion and contraction of the patches due to changes in weather and temperature conditions which facilitates the introduction of water beneath the patch and surrounding roadway. If water seeps through the patched area, it will spread to the base and sub-base of the roadway, causing continuing disintegration of the roadway as a result of the perma-frost effect, leading to more extensive repairs and an attendant increase in costs for repairing the road.
Cold asphalt mixes containing cut-back asphalts, slow-curing asphalts and emulsified asphalts which can be stock-piled are in common use today. These mixtures depend upon the evaporation of solvents or water to cause sufficient hardening to prevent displacement under traffic. Quite often, however, these cold patches are displaced by traffic before complete hardening is achieved, resulting in the need for the additional application of a cold patching composition at the repair site. In addition, cold asphalt mixes, such as those in the form of emulsions, are generally not stable over long periods of time and generally must be used shortly after the preparation thereof to prevent the separation of the ingredients of the compositions. An example of an asphalt composition in the form of an emulsion containing water is disclosed in U.S. Pat. No. 3,867,162 to Elste, Jr.
A need therefore exists for a patching composition that is capable of overcoming the various disadvantages associated with various prior art compositions.